There are numerous lock solutions presented in patent and non-patent literature. The term lock should denote, apart from the usual door locks of various kinds, the lock for the vehicle steering wheels, as well as all kinds of special locks such as padlocks and other. Theoretically, there are several groups of locks that are different from each other by way of locking/unlocking. There are also locks with rotary keys which move the lamellar arresters perpendicularly to the key, locks having arresters which adjust by putting in the key, locks in which the slide valve is moved by means other than the key, locks with permutations, locks with display devices or time counters, locks for special purposes, etc. The most common types of locks are the cylinder locks with arresters in the shape of pins or small balls and cylinder locks with lamellar arresters.
One known solution of the lock is the Yugoslav patent application no. P-731/92 in which the cylinder lock made up of a cylinder and a key is presented. The cylinder is profiled as a semi cylinder and contains a cylinder housing that at its upper, essentially round cylinder part, contains longitudinal opening of the core for the installation of the cylinder core. The cylinder core bears the element for locking on its inwardly located end. The rotation of the cylinder core is in that manner conveyed to lock elements. The lock element remains axially immovable in the slit of cylinder housing. The flange part of the cylinder housing extends radially to the round cylinder part. The housing through-holes arranged in the succession, which also extend radially to the core of the cylinder, are to be put in the flange part. Their ends, far from the cylinder core, are sealed helped by the keys. These housing through-holes serve to hold the springs of keys as well as the keys themselves. The core through-holes are oriented radially in relation to the cylinder core to hold the linchpins, which are straightened with the housing through-holes. The housing keys and the core keys form a limiter, which prevents the rotating of the cylinder core and thus the lock elements, too, as the key is not put in. The core wedges move only by putting in the appropriate key in the channel in the cylinder core, so that the special link between the core wedges and the housing wedges is located on the level of the sliding link of the cylinder core.
Another known solution has been presented in the patent document YU PS 45139 entitled “Cylinder Lock with Double Locking of Cylinder”. This solution relates to a cylinder lock with double locking of cylinder in which the locking of the cylinder is achieved from two sides, by different systems of linchpins and lifter by using a profiled key, so that from the lower part of the cylinder the standard system of shutting linchpins and lifters is used, under the influence of springs, and from the above the system of sealing linchpins and lifters placed in the upper part of the vertical plane, which passes through the cylinder axis, and is movable under the influence of the gravitation force. Apart from that, in the middle the cylinder grooves are made into which the plates are put, what serves for the purpose of preventing the unlocking of the upper system by various objects.
Other relevant known solutions are presented in Yugoslav patent applications P-500/98 in which the programmed cylinder lock with main keys is shown, P-1812/80 in which the profiled cylinder lock is presented, P-678/92 presenting the steering wheel lock, P-1487/86 presenting the blocking safety lock for motor vehicles, etc.
Main disadvantages of the known locks, some of which are in the above passage, are complicated construction, possibility of breaking, small number of coding combinations are limitation in use.